Metronome

ABSTRACT

A metronome is disclosed which employs a plurality of potentiometers equal in number to the desired output frequencies. The potentiometers are individually adjusted and individually connected into a timing circuit through the action of a switch which operates in detent fashion.

United States Patent .Alessio 5] Sept. 19, 1972 1 METRONOME 3,038,126 6/1562 Bernstein et al ..58/l30 E X [72] inventor: Ralph D. Alesslo, Waterbury, Conn. Q

[73] Assignee: Tele-Conn Enterprises, Inc., Woln Com-l- Primary Examiner-Richard B. Wilkinson I Assistant Examiner-John F. Gonzales [22] filed: 1971 Attorney-David S. Fishman et al.

[21] Appl. No.: 213,278 ABSTRACT I A metronome is disclosed which employs a plurality of [521 :LS. Cl ..84/484, 58/130 E, 340/384 b potentiomeers equal in number to the desired output [5 lit. C ..G10b 15/00 frequencies The Potentiometers are individually [58] F'eld Search 34/484; 58/13 R, 130 A, 130 justed and individually connected into a timing circuit 53/130 340/384 384 371 through the action of a switch which operates in detent fashion. [56] References Cited 19 Claims, 4 Drawing Figures UNITED STATES PATENTS '7 I l v v A l 2,522,492 9/ 19 5 0 Andersen .340/38 4 R UX 4O 4O 46 R R SC 59 G DI 57 P SHEET 2 [IF 2 v PAIENIEDSEP 19 m2 BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates'to the production of audible sounds at a plurality 'of different and preselected frequencies or beats. More specifically this invention is directed to a novel and improved metronome. Accordingly, the general objects of the present invention are to provide novel and improved. methods and apparatus of such character.

2. Description of the Prior Art Metronomes, and particularly key wound metronomes of the type generally known in the art as Maelzel metronomes, havebeen known-for almost 200 years. The typical prior art metronome was a mechanical'device wherein the position. of a weight was moved between detents on a pendulum rod to vary output frequency. Recently, a number of eIectro-mechanical metronomes have been introduced. The electromechanical metronomes are generally preferred in spite 'of their excessive cost when compared to mechanical devices of like character in view of their compactness, easeof adjustment and high degree of accuracy which is maintained over the life. of the metronome. However, prior art electro-mechanical metronomes have nevertheless been difficult to use since frequency adjustment was achieved by repositioning the wiper arm of one or more rheostats and the resistance of the rheostats did not vary linearly in accordance with standard Maelzel scale graduations.

SUMMARY OF THE INVENTION The present invention overcomes the above briefly discussed and other disadvantages of the prior art by providing a novel and improved electro-mechanical metronome. In accordance with'the invention, an RC timing network employing discreetly selected and individually adjusted potentiometers in combination with a fixed capacitor determines metronome output frequency. The timing network cooperates with-a voltage sensitive threshold type semiconductor todefine an oscillator which delivers current pulses at theselected output frequency to an electro-magnetic sound producing device. A particularly novel feature of the invention resides in a physical arrangement of components on a printed circuit board which enables selection of each timing sequence in a detented fashion. A high'degree of accuracy is achieved by calibrating each discreet potentiometer of the timing network to the desired beat rate. The individual calibration of each timing sequence permits a lineargraduation'of timing periods on the Maelzel scale.

BRIEF DESCRIPTION OFTI-IE DRAWING The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawing wherein like reference numerals refer to like elements in the several figures and in which:

FIG. 1 is an electrical schematic of a preferred embodiment of a metronome in accordancewith the invention;

FIG. 2 is a side elevation view of a first embodiment of the present invention;

FIG. 2A is a side elevation view of a preferred embodiment of the present invention; and

FIG. 3 is the front elevation view of the printed circuit side of a circuit board employed in a third embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 2 and 2A, the invention comprises a stationery front support plate and/or dial 10 on which the scale graduations may be imprinted. Plate 10 is connected, via a plurality of transverse support members such as threaded rods and associated fasteners as indicated at 12 and 14, to a stationery printed circuit board 16. The electrical circuit components of the metronome, which have been omitted from Figures 2 and 2A in the interest of clarity, will be mounted on the side of circuit board 16 which faces away from plate 10.

A retaliate" shaft l8' passes through both circuit board 18 and plate 10 and is oriented transversely with respect thereto. Suitable means are employed to prevent inadvertent withdrawal of shaft 18 from the apertures provided therefor in circuit board 18 and plate 10. The end of shaft 18 which extends forwardly from plate 10 is provided with a flat which is engaged by a knob 20. The knob has a pointer 22 extending outwardly therefrom parallel to the face of plate 10. Pointer 22. will move with relation to the scale imprinted on the face of plate 10 and the output frequency of the metronome may be selected, in a manner to be described below, by'rotation of knob 20 so that the pointer 22 lines up with the selected output frequency indicia.

A wheel 24 is positioned between plate 10 and circuit board 16 and keyed or otherwise attached to shaft 18. The requisite spacing between wheel 24 and plate 10' and circuit board 16 is assured by the use of tubular spacers mounted on shaft 18; spacer 26 preventing motion of wheel 24 towards plate 10 and spacer 28 preventing movement of wheel 24 toward circuit board 16. Wheel 24 will be molded from aninsulating material such as a suitable phenolic resin.

A wiper arm 30'will be attached to wheel 24 by means of a rivet 32 or other suitable means. Wiper arm 30 will typically be comprised of a phosphor-bronze alloy and will be provided at its opposite ends with bent over portions which define contacts 34 and 36. Wiper arm 30 will 'be spring loaded against printed circuit board 16 and selection of the material for arm 30 will be dictated by the need for electrical conductivity coupled with the ability to retain resiliency. The contacts, 34 and 36 of arm 30 may, if desired, be coated with gold to minimize friction, insure a good electrical contact and inhibit pitting.

Referring to FIG. 3, it will be noted that printed circuit board 16 is provided with an inner circular contact 38 which defines a planar outer surface; this surface facing inwardly in the assembly shown in FIG. 2. Contact 36 of arm 30 will slide on the surface of ring 38 whereby a constant electrical connection is established between ring 38 and arm 30. Contact 34 of wiper arm 30 will be moved, as knob 20 and thus wheel 24 is rotated, between a series of contacts 40 on board 16;

the contacts 40 being arranged in a circle as shown in FIG. 3.

Referring to FIG. 1, an electrical schematic of the present invention is shown. In the interest of facilitating understanding of FIG. 1, the stepping switch defined by wiper arm 30 and the contact areas on printed circuit board 16 has been shown as a plurality of separate switches. The timing circuit of the present invention comprises a basic RC type of timing circuit. A timing capacitor C, and an appropriate size resistance, as established by a potentiometer R selected by switch 30, will be connected in series across a DC voltage source 42. Voltage source 42 may be either a battery or a conventional rectifier-type power supply. The timing circuit also employs a normally non-conductive solid state device which preferably will be of the breakdown" diode type. The solid state device, shown in FIG. 1 as a silicon unilateral switch (SUS) D may comprise General Electric type D13P1. A silicon unilateral switch is a diode thyristor which is particularly well suited for monostable applications. The anode of diode D is connected to the common junction between capacitor C1 and the selected potentiometer R1. The coil 44 of an electro-magnetic striker assembly is connec b w n bs sethosis of @951? .9132! ar potential. Each time capacitor C1 charges up to the forward switching voltage of diode D the diode conducts thus discharging capacitor c'ifiioiigfifificanili to ground; the resulting current pulse through the coil producing a magnetic field. The gate electrode of diode D, is left unconnected.

The striker mechanism includes, as noted above, a coil 44 which has a core 46 operatively associated therewith. One end of core 46 is positioned adjacent to and transversely of a metal diaphragm insert 48 cemented over a hole in a sounding board 50. The sounding board will typically be comprised of balsa wood and diaphragm 48 will typically be comprised of soft iron. The audible output tone of the device will be determined by the size and mounting of diaphragm 48 and sounding board 50 and an output sound pulse will be produced each time diode D1 conducts; conduction of the diode causing a current pulse to flow through solenoid 44 thus generating a magnetic field which attracts diaphragm 48 causing it to strike core 46.

As previously noted, the present invention, employs a plurality of potentiometers R1. Although only two potentiometers are depicted in FIG. 1, it will be understood that there will typically be 39 individually adjusted potentiometers to correspond to the standard Mael'zel scale. It should also be noted that prior art metronomes typically employ a single rheostat rather than a plurality of potentiometers. In the interest of precision, the present invention employs a plurality of linear potentiometers which are connected as rheostats as shown in FIG. 1; the actual connections being made on the printed circuit board 16. With reference to FIG. 3, the potentiometers are mounted on the rearwardly facing side of circuit board 16 and the end terminals of the potentiometers are connected to contacts 52 and 54 of the printed circuit board while the wiper arms of the potentiometers are connected to printed circuit board terminals 56. Capacitor C1 is connected between board terminals 57 and 58 while diode D1 is connected between terminals 57 and 59. Coil 44 is connected between terminals 60 and 61, the negative terminal of source 42 is connected to terminal 61 and the positive terminal of source 42 is connected to contact ring 38.

Referring again to FIG. 2, in accordance with a first embodiment of the invention the periphery of wheel 24 is serrated so as to provide a plurality of detents or stops which correspond to points of contact between contact 34 of wiper arm 30 and the spaced circuit board contacts 40. The serrations on wheel 34 are indicated at 62 and cooperate with a spring member 63 mounted from support member 12. Accordingly, in the embodiment of FIG. 2, rotation of knob 20 will cause spring 63 to step between serrations 62 on wheel 24 and the metronome output frequency will be selected in positive and stepwise fashion.

Referring to FIG. 2A, in the preferred embodiment of the invention printed circuit board 16' is of circular shape and is provided with the serrations 62 in its periphery thereby providing the plurality of stops which correspond to points of contact between wiper arm 30 and the spaced circuit board contacts 40. In the FIG. 2A embodiment the rotatable shaft 18 is extended past the rear side of circuit board 16' and an elongated spring arm 64 is keyed to the shaft. The outwardly disposed end of arm 64 carried a spring member 63' which cooperates with the serrations 62 in the edge of circuit board 16. Thus, as in the FIG. 2 embodiment, rotation of knob 20 of the FIG. 2A device will cause spring 63' to step between serrations 62 on fixed posi tion printed circuit board 16' and the metronome output frequency will be selected in positive and stepwise fashion.

In accordance with a third embodiment of the invention, as depicted in FIG. 3, the spaced contacts 40 on printed circuit board 16 will be provided with depressions or holes which will be engaged by the contact end 34 of wiper arm 30. As in the case of the FIG. 2 embodiment, the FIG. 3 embodiment will insure precise, stepwise selection of the output frequency. If contacts 40 are provided with detent means the spring 63 and serrations 62 of the embodiments of Figures 2 and 2A be omitted.

It is to be noted that the physical location of the stroker and sounding board is not critical and these components can either be within the same package as the structure depicted in FIG. 2 or at a remote location.

The circuit defined by the conductive areas and contacts on printed circuit board 16 will be the same for all three disclosed embodiments.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

What is claimed is:

1. A metronome comprising:

pulse generator means, said pulse generator means including a timing circuit for generating output pulses at a selected one of a plurality of repetition rates, said pulse generator means including adjustable resistance elements equal in number to the available output pulse repetition rates;

switch means for individually selecting and connecting said adjustable resistance elements in said timing circuit of said pulse generator means;

means for supporting said switch means and said pulse generator means in adjacent spaced relationship; and

transducer means responsive to output pulses generated by said pulse generating means for producing an audible output signal.

2. The apparatus of claim 1 wherein said resistance elements of said pulse generating means each comprises:

a potentiometer.

3. The apparatus of claim 2 wherein said pulse generating means further comprises:

a direct current source;

capacitor means;

means electrically connecting the selected potentiometer and said capacitor means in series across said source;

means connecting each of said potentiometers as a rheostat; and

electronic switch means connected between said capacitor means and said transducer means, said electronic switch means being responsive to the charge stored in said capacitor means for periodically establishing a discharge path for said capacitor means through said transducer means.

4. The apparatus of claim 3 wherein said electronic switch means comprises:

a voltage sensitive diode.

5. The apparatus of claim 1 wherein said pulse generator means includes a printed circuit board having contact portions on a first side thereof which faces said switch means, said contact portions being engaged by and cooperating with said switch means to connect the selected resistance element in the timing circuit.

6. The apparatus of claim 5 wherein said switch means comprises:

nonconductive base means;

a pair of contact members extending outwardly from said base means, said contact members being electrically connected to one another and engaging said printed circuit board; and

means mounting said base means on said supporting means for rotation in a plane parallel to the plane of said printed circuit board first face.

7. The apparatus of claim 6 wherein said base means comprises:

a disc of nonconductive material, said disc being provided with a plurality of recesses in its periphery.

8. The apparatus of claim 7 wherein said supporting means further comprises:

resilient means for engaging said recesses in said disc periphery whereby said disc may be moved in stepwise fashion.

9. The apparatus of claim 6 wherein said first face of said circuit board defines, a circular common connection which is continuously contacted by a first of said contact members and a plurality of spacially displaced second contacts arranged in a circular pattern so as to be contacted by the second of said contact members, all of the said potentiometers being mounted on the second face of said printed circuit board and having 6 first end terminals thereof connected to said circular contact and respectively having second end terminals connected to individual of said spaced second contacts.

10. The apparatus of claim 8 wherein said first face of said circuit board defines a circular common connection which is continuously contacted by a first of said contact members and a plurality of spacially displaced second contacts arranged in a circular pattern so as to be contacted by the second of said contact members, all of the said potentiometers being mounted on the second face of said printed circuit board and having first end terminals thereof connected to said circular contact and respectively having second end terminals connected to individual of said spaced second contacts.

11. The apparatus of claim 9 wherein said second contacts are provided with recesses which are engaged by the end of said second contact member whereby the available output pulse repetition rates may be selected in step-wise fashion.

12. The apparatus of claim 6 wherein said pulse generating means comprises:

a direct current source;

capacitor means;

conductor means on said printed circuit board for connecting the selected resistance element and said capacitor means in series across said source; and

voltage sensitive switch means connected between said capacitor means and said transducer means, said voltage sensitive switch means periodically establishing a discharge path for said capacitor means through said transducer means.

13. The apparatus of claim 12 wherein said base means comprises:

a disc of nonconductive material, said disc being provided with a plurality of recesses in its periphery.

14. The apparatus of claim 13 wherein said supporting means further comprises:

resilient means for engaging said recesses in said disc periphery whereby said disc may be moved in stepwise fashion.

15. The apparatus of claim 6 wherein said printed circuit board is provided with a plurality of recesses in its periphery and wherein said mounting means further comprises:

spring arm means for engaging said recesses in said printed circuit board periphery whereby said base means may be moved in stepwise fashion.

16. The apparatus of claim 6 further comprising:

ratchet means mounted on said supporting means and permitting the movement of said switch means contact members in stepwise fashion.

17. The apparatus of claim 9 further comprising:

ratchet means mounted on said supporting means and permitting the movement of said switch means contact members in stepwise fashion.

, 18. The apparatus of claim 17 wherein said ratchet means comprises:

a plurality of recesses spaced about the periphery of said printed circuit board and corresponding to said spacially displaced second contacts; and

spring arm means affixed to and rotating with said mounting means, said spring arm means engaging said recesses in the periphery of said circuit board.

19. The apparatus of claim 18 wherein said pulse generating means comprises:

a direct current source;

capacitor means;

conductor means on said printed circuit board for said capacitor means and said transducer means, connecting the selected resistance element and Said voltage ensitive switch means periodically said capacitor means in series across said source; establishing a 8 Pa for Said capacitor and means through said transducer means.

voltage sensitive switch means connected between 

1. A metronome comprising: pulse generator means, said pulse generator means including a timing circuit for generating output pulses at a selected one of a plurality of repetition rates, said pulse generator means including adjustable resistance elements equal in number to the available output pulse repetition rates; switch means for individually selecting and connecting said adjustable resistance elements in said timing circuit of said pulse generator means; means for supporting said switch means and said pulse generator means in adjacent spaced relationship; and transducer means responsive to output pulses generated by said pulse generating means for producing an audible output signal.
 2. The apparatus of claim 1 wherein said resistance elements of said pulse generating means each comprises: a potentiometer.
 3. The apparatus of claim 2 wherein said pulse generating means further comprises: a direct current source; capacitor means; means electrically connecting the selected potentiometer and said capacitor means in series across said source; means connecting each of said potentiometers as a rheostat; and electronic switch means connected between said capacitor means and said transducer means, said electronic switch means being responsive to the charge stored in said capacitor means for periodically establishing a discharge path for said capacitor means through said transducer means.
 4. The apparatus of claim 3 wherein said electronic switch means comprises: a voltage sensitive diode.
 5. The apparatus of claim 1 wherein said pulse generator means includes a printed circuit board having contact portions on a first side thereof which faces said switch means, said contact portions being engaged by and cooperating with said switch means to connect the selected resistance element in the timing circuit.
 6. The apparatus of claim 5 wherein said switch means comprises: nonconductive base means; a pair of contact members extending outwardly from said base means, said contact members being electrically connected to one another and engaging said printed circuit board; and means mounting said base means on said supporting means for rotation in a plane parallel to the plane of said printed circuit board first face.
 7. The apparatus of claim 6 wherein said base means comprises: a disc of nonconductive material, said disc being provided with a plurality of recesses in its periphery.
 8. The apparatus of claim 7 wherein said supporting means further comprises: resilient means for engaging said recesses in saId disc periphery whereby said disc may be moved in step-wise fashion.
 9. The apparatus of claim 6 wherein said first face of said circuit board defines a circular common connection which is continuously contacted by a first of said contact members and a plurality of spacially displaced second contacts arranged in a circular pattern so as to be contacted by the second of said contact members, all of the said potentiometers being mounted on the second face of said printed circuit board and having first end terminals thereof connected to said circular contact and respectively having second end terminals connected to individual of said spaced second contacts.
 10. The apparatus of claim 8 wherein said first face of said circuit board defines a circular common connection which is continuously contacted by a first of said contact members and a plurality of spacially displaced second contacts arranged in a circular pattern so as to be contacted by the second of said contact members, all of the said potentiometers being mounted on the second face of said printed circuit board and having first end terminals thereof connected to said circular contact and respectively having second end terminals connected to individual of said spaced second contacts.
 11. The apparatus of claim 9 wherein said second contacts are provided with recesses which are engaged by the end of said second contact member whereby the available output pulse repetition rates may be selected in step-wise fashion.
 12. The apparatus of claim 6 wherein said pulse generating means comprises: a direct current source; capacitor means; conductor means on said printed circuit board for connecting the selected resistance element and said capacitor means in series across said source; and voltage sensitive switch means connected between said capacitor means and said transducer means, said voltage sensitive switch means periodically establishing a discharge path for said capacitor means through said transducer means.
 13. The apparatus of claim 12 wherein said base means comprises: a disc of nonconductive material, said disc being provided with a plurality of recesses in its periphery.
 14. The apparatus of claim 13 wherein said supporting means further comprises: resilient means for engaging said recesses in said disc periphery whereby said disc may be moved in step-wise fashion.
 15. The apparatus of claim 6 wherein said printed circuit board is provided with a plurality of recesses in its periphery and wherein said mounting means further comprises: spring arm means for engaging said recesses in said printed circuit board periphery whereby said base means may be moved in stepwise fashion.
 16. The apparatus of claim 6 further comprising: ratchet means mounted on said supporting means and permitting the movement of said switch means contact members in stepwise fashion.
 17. The apparatus of claim 9 further comprising: ratchet means mounted on said supporting means and permitting the movement of said switch means contact members in stepwise fashion.
 18. The apparatus of claim 17 wherein said ratchet means comprises: a plurality of recesses spaced about the periphery of said printed circuit board and corresponding to said spacially displaced second contacts; and spring arm means affixed to and rotating with said mounting means, said spring arm means engaging said recesses in the periphery of said circuit board.
 19. The apparatus of claim 18 wherein said pulse generating means comprises: a direct current source; capacitor means; conductor means on said printed circuit board for connecting the selected resistance element and said capacitor means in series across said source; and voltage sensitive switch means connected between said capacitor means and said transducer means, said voltage sensitive switch means periodically establishing a discharge path for said capacitor means through said transducer means. 